1. Field of the Invention
The present invention relates to a rollbar apparatus for protecting occupants of a vehicle. More specifically, the present invention relates to a double hoop rollbar for use in passenger cars and trucks.
2. Background Information
In cars and trucks, rollbars are often provided for both roll-over protection and for aesthetic purposes. Rollbars are particularly popular in convertible type cars and roadsters, because of the lack of a rigid roof structure. Aesthetic “style” bars are often installed just for looks, and generally include a chrome or other bright finish to make them visually attractive. Other rollbars are provided for protection against injury in the case of a rollover, especially in sports or racing cars which are driven aggressively.
These functional rollbars extend slightly above the heads of the occupants, to protect them in the event of a vehicle rollover. There are two basic types of rollbars. The first type is a single hoop style. The second type is a double hoop style. The single hoop rollbar has one main hoop which spans from one side of the vehicle to the other side. The double hoop rollbar generally utilizes a smaller hoop behind each of the front seats. Both styles often have brace bars or structural members to support their shape. In addition, rollbars can be bolted or welded into position. Also, additional structural bars can be added to the basic rollbar to form a roll cage, which can more thoroughly protect the occupants of the vehicle.
For double hoop style rollbars, the hoops each have an inner leg which needs to be supported in the center of the car. For rollbars which do not provide protection to the occupants, this support is usually a single bent tube attached only to the sides of the vehicle. For double hoop rollbars with the stated intent of occupant protection, these inner legs must be supported in a more substantial manner.
Some vehicles, especially smaller vehicles, do not have adequate structure or access to support the inner legs in the center of the vehicle. In addition, the tight clearances between the seats and the body of the vehicle severely limit the mounting of traditional double hoop rollbar structures. As a result, rollbars intended for protection of the occupants in certain vehicles have been limited to single hoop type structures.
In prior art single hoop rollbars, the top bar of the hoop is often in line with the rearview mirror, partially obscuring rearview vision. There are often brace bars that attach to the center of the single hoop, further interfering with rearview vision. These brace bars are required on a single hoop rollbar to reinforce the center section of the hoop.
Also, it is a common practice in small roadsters to be able to raise the convertible top while sitting in the driver seat. In the prior art single hoop rollbars, this is not possible.
In the prior art double hoop rollbars, some vehicle manufacturers have provided factory installed structural hoop shapes that attach to the seat backs. However, this requires a much more rigid seat structure and thus additional cost. In addition, if alternate seats such as racing seats are installed, the rollbars are also removed, and must be replaced. The hoops which install in the seat backs are also limited in size to the width of the seat, and cannot be easily customized.
Some vehicle manufacturers have chosen not to provide rollover protection for their vehicles. In these cases, there is no provision for the center support required for a structurally sound rollbar, thus an alternative method must be developed for those owners wishing to have rollover protection with the visual appeal of a double hoop rollbar.
The present invention overcomes the problem of inadequate center support by providing a method of support for the inner legs of the double hoop rollbar. The present invention provides a joining member between the inner rollbar legs and a method of attaching the inner rollbar legs to other structural points of the vehicle. The joining member can be made of square or round tubing, flat bar, or any other structural shape. In order to facilitate ease of installation and shipping, the joining member can be comprised of several different parts, which are fastened together during final assembly of the apparatus. This joining member assembly can include flat plates or angles bolted together, or tubing with telescoping sleeves which are fastened together.
The joining member and inner rollbar legs will sometimes utilize one or more support legs, which contact the body of the vehicle. The support legs can be made of any structural component, including flat steel plate, angles, tubes, or even synthetic materials such as plastic or nylon. Some support legs will be relatively long, or could be simple spacer blocks or washers. In some applications, the joining member, inner rollbar legs, or support legs could be held in place using existing vehicle body structure, without the use of additional fasteners.
It is desirable to have an improved design for a rollbar apparatus which allows the double hoop style structure to be used, while maintaining the rigidity and center support required for rollover protection.
Thus, one of the objectives of the present invention is to provide a double hoop rollbar apparatus which overcomes the problems associated with prior art devices and makes a considerable contribution to the art of rollbar design. Depending on the embodiment of the present invention, the advantages include, for example:    (a) providing a rollbar which is intended to protect the occupants of a vehicles which do not have adequate mounting structure near the center of the vehicle;    (b) providing a rollbar which is an alternative to factory mounted rollbars, without forfeiting a level of rollover protection;    (c) providing a rollbar which is intended to help protect the occupants of a vehicle, without obstructing the view through the rearview mirror;    (d) providing a rollbar which is intended to help protect the occupants of a vehicle without limiting the ability to raise and lower the convertible top from the driver's seat;    (e) providing a joining member between the inside legs of the double hoops, to provide lateral strength to the structure;    (f) providing a rollbar which consists of several parts fastened together, so that easy shipping, installation, and removal of the structure is possible;
Therefore, it is a primary feature of the present invention to provide a rollbar apparatus which overcomes the aforementioned problems associated with the prior art rollbars and which provides a significant contribution to the art of automotive rollover protection.
Other features and advantages of the rollbar apparatus according to the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained herein of a preferred embodiment of the present invention.